Explain the concept of routing in Flutter.

Routing in Flutter refers to the process of navigating between different screens or pages within an app. Flutter provides a robust routing system to manage navigation effectively.

Here’s a step-by-step explanation of how routing works:

1. Define Routes: You can define routes in the MaterialApp widget using the 'routes' property.
2. Navigate: Use Navigator.push() to navigate to a new route and Navigator.pop() to return to the previous one.
3. Named Routes: Use named routes for easier management of navigation.

Example code snippet:

void main() {
  runApp(MaterialApp(
    routes: {
      '/': (context) => HomeScreen(),
      '/details': (context) => DetailsScreen(),
    },
  ));
}

// Navigate to details screen:
Navigator.pushNamed(context, '/details');